You even call your method a "workaround".2. Installation and Use Rights.
c. Restrictions. The manufacturer or installer and Microsoft reserve all rights (such as rights under intellectual property laws) not expressly granted in this agreement. For example, this license does not give you any right to, and you may not:
(iv) work around any technical restrictions or limitations in the software;
And then - and I'll have to switch computers to quote it - but the EULA for the evaluation builds of Windows 10 are for evaluation and testing ONLY - not using that build as a basis to obtain a free upgrade to a new installation of Windows 10 that the user would not otherwise qualify for without upgrading from a fully licensed and activated Windows 7/8/8.1.
What build did you have? If you kept up with the insider program you would have had build 10240 which is identical to the released version of Windows 10. You could have kept it and stayed with the insider program and would currently be at build 10547. Or you could have left the insider program and as long as you started with a legal, activated Win 7, 8 or 8.1 that would have been it and you would have been at the RTM level and no longer an insider.
See the post by Andre Da Costa here for more info on this if you're interested: http://answers.microsoft.com/en-us/w...0-90aff47aa1ce
Yes I realize this is not allowed by the EULA. Sorry, I didn't mean to help getting Windows 10 illegally, I just said there is a way to install Windows final in Insider. To be legal though you should upgrade from 7 or 8.1
A previous insider build may only have a product key activation which may not have created an activation entitlement on the MS server.